Automatic rock drilling means



May 7, 1968 c. A. HANSSON AUTOMATIC ROCK DRILLING MEANS 4 Sheets-Sheet 1 Filed Oct. 13, 1965 INVENTOR. C'md flndeas Hansson BYW mm w us, my

7, W58 c. A. HANSSON AUTOMATIC ROCK DRILLING MEANS 4 Sheets-Sheet 2 Filed Oct. 13. 1965 NVENTOR. Cml hmleas \unssun May 7, 1968 c. A. HANSSON AUTOMATIC ROCK DRILLING MEANS 4 Sheets-Sheet 3 Filed Oct. 13. 1965 I IN CM M6615 H VENTOR. N550 q m, WY

Ks Mung 4 Sheets-Sheet 4 INVENTOR. C 0.9.! RndzRS Human May 7, 1968 c. A. HANSSON AUTOMATIC ROCK DRILLING MEANS Filed Oct. 13, 1965 QM QM Q9 8 x V m... w x 3 R ms 23$ 8 Q MDT NQ- Q8 w NY 0% Nb u QR Q m Z Unit ABSTRACT OF THE DISCLOSURE Automatic rock drilling apparatus is provided as powered and controlled by pressure fluid and including a rock drill fed along a supporting shell therefor by a reversible feed motor which provides for automatically defining the depth of a hole to be drilled. The feeding direction of the motor is controlled by means of a reversing valve shiftable from a forward to a backward feed position by a servo motor. A limit switch valve actuated by the rock drill is provided forwardly on the shell and is included in a servo circuit together with the servo motor for automatically defining the depth of the hole drilled by creating a pressure condition in the servo motor causing shifting of the reversing valve to the backward feed position when the forward limit switch valve is actuated by the drill. A flushing valve is also included and controlled by a servo circuit coupled in parallel with the feed motor for directing flushing liquid or air to the drill steel of the rock during, respectively, forward and backward feed movement thereof. Also included is a servo motor and valve device in which a pressure fluid actuated servo motor housing is the plug in a rotary plug valve for controlling the pressure fluid supply to the rock drill. The plug passage in the valve is closed and opened by a plunger movable by the servo motor in the housing with this movement being released in response to the rock drill actuating the forward limit switch valve in order to cut down the pressure fluid supply during backward feed movement of the rock drill.

This invention relates to automatic rock drilling means including a rock drill which by means of a reversible feed motor is movable from a starting position on a supporting shell to a forward reversing position thereon corresponding to the desired drill hole depth and automatically back again to the starting position. It is a primary object of the invention to provide an effective and functionally dependable automation of the reciprocating movement of the rock drill.

For performing the drilling process without disturbances it is necessary to maintain an effective flushing of the drill hole so that the drill cuttings are removed from the hole. It is therefore a further object of the invention to provide in a rock drilling means an automatically alternating flushing character capable of enhancing the effectivity of automatic drilling.

In an automated drilling process for percussive rock drills it is important during backward feed movement of the rock drill to automatically prevent delivery of full power to the impact motor in order to protect the rock drill against breakage during idle running. It is therefore another object of the invention to provide an automatic reduction or cut-off of power delivered to the rock drill during its return or backward movement along the supporting shell.

Hereinafter conduits, hoses, valves and valve elements of standard construction used in connection with the automatic means are only shown diagrammatically and in easily understandable symbols. The detailed construction States Patent of the various valves and the connection of the conduits is well known in the art and is therefore for purposes of simplification not described in detail.

The invention is described more in detail by the aid of the enclosed drawings in which FIG. 1 shows a circuitry for pneumatic automation of rock drilling means. FIG. 2 shows a longitudinal enlarged section through a manoeuvering valve included in the pneumatic circuitry depicted in FIG. 1. FIG. 3 is a side view of the valve depicted in FIG. 2. FIG. 4 shows an end view and section on the line 4-4 in FIG. 3. FIG. 5 shows a front view of the valve depicted in FIG. 2. FIG. 6 shows a fragmentary enlarged section on the line 6-6 in FIG. 5. FIG. 7 is a developed view of the peripheral surface of the valve shown in FIG. 6. FIGS. 8-10 show an enlarged section on the line 88 in FIG. 2 illustrating three different position of the valve depicted in FIG. 6. FIG. 11 finally is a modified circuitry for pneumatic automation of the rock drilling means.

In FIG. 1 10 is a pneumatic percussive rock drill mounted on a slide 11, which is slidably and reciprocably mounted on suitable guides of an elongated supporting shell 12. The slide 11 contacts in a starting position of the rock drill 10 a rear abutment 13 on the shell 12 and contacts in the forward turning position thereof a forward abutment 14. The rock drill 10 carries a drill steel 15, which in well-known manner is guided by means of a drill steel guide 16. The shell 12 is normally carried by a supporting and positioning boom, not shown, which preferably is operated by hydraulic means. During drilling an abutment member 17 rests against the rock face.

A pneumatic feed motor 18 is fixed to the feed shell 12 and drives for example via a chain 19 connected to the slide 11 and placed over chain wheels 20, 21 at the opposite ends of the shell 12 the slide 11 in forward or rearward direction along the feed shell 12 depending on the direction of rotation of the feed motor 18.

Compressed air is delivered from a source, not shown, via a conduit 30 to a main valve 31. The main valve 31 includes a valve diaphragm 32 of rubber which closes against a fixed valve seat 29 under the action of a spring 35. Servo piston means consisting of a servo diaphragm 33 in a servo cylinder 34, which also houses the spring 35, are adapted to release the valve diaphragm 32 when the servo diaphragm 33 receives compressed air at its underside for compression of the spring 35. During such compression ithe valve diaphragrm 32 is opened by the pressure in the conduit 30. When the underside of the servo diaphragm 33 is exhausted to the atmosphere the main valve 31 is closed by the spring 35 urging the valve diaphragm 32 against its seat 29.

The conduit 30 communicates via the main valve 31 with a main conduit branch 38. The branch 38 is connected to a through passage 36 in a manoeuvering valve 39 in which is rotatably and sealingly journaled a cylindrical valve plug 40 having a diametrical through passage 37, FIG. 2. The plug 40 is adjustable by means of a handle 41 to suitable angular positions for controlling the air flow to the impact motor of the rock drill 10 which is coupled to the valve 39 by means of an air hose or conduit 42.

To the manoeuvering valve 39 is also connected at flushing Water conduit 43 which is controlled by means of a Water valve plug 44 mounted coaxially with the manoeuvering valve plug 40. The plug 44 is journalled sealingly and rotatably in the manoeuvering valve 39 and can be adjusted angularly by means of a handle 45. Normally the handles 41 and 45 are interconnected-by means of a latch 46 whereby simultaneous control of flushing water and operating air is provided. The latch 46, FIG. 4, is axially slidably journalled in a hand grip 23 connected to the handle 45 and projects into a bore 24 in the handle 41. A cam member having a finger trigger thereon is fixed axially to the latch 46 and projects with the cam portion thereof into a cooperating cam groove in a cam bushing 26 fixed to the outer end of the hand grip 23. When the cam member 25 is turned by means of its trigger it will be displaced axially through cam action to a retracted position on the outer face of the cam bushing 26, FIG. 5, whereby the latch 46 is retracted from the bore 24 and the handles 41, can be actuated independently from one another. A spring 27 acting between the cam bushing 26 and a pin 28 passing diametrically through the latch 46, is active to move the latch 46 axially towards the bore 24 where the cam portion v of the cam member 25 is aligned with the cam groove of the cam bushing 26.

From the main branch 38 compressed air is conducted via a conduit 47 to a flushing valve and to this flushing valve is also connected a flushing water conduit 48 via the water valve plug 44 in the manoeuvering valve 39. By pressure fluid actuation of servo piston means 50a and 50b provided at the opposite ends of the flushing valve 50, the latter can be moved respectively to a position a and a position b. In the position a, FIG. 1, water from the conduit 48 is led through the flushing valve 50 on to a hose or conduit 49 which in per se well known manner is connected to a flushing tube 22 at the rear end of the rock. drill whereby flushing water is conducted to the axial passage of the drill steel 15. In the position b of the flushing valve 50 the water conduit 48 is closed and instead the air conduit 47 is coupled to the conduit 49 whereby the drill hole is flushed by air.

A reduction valve plug 51, FIGS. 1, 2 and 6-10, is sealingly and rotatably journalled in the manoeuvering valve 39 and provided with a handle 52 for the angular adjustment thereof. The plug 51 has an axial bore 53 therein, by which it communicates with the through passage 36 of the manoeuvering valve 39. From the bore 53 there extend two oppositely directed radial bores 68 and 68 An annular peripheral groove 56 surrounds the base portion of the plug 51 and is connected to the ambient atmosphere via a radial hole 59 in the manoeuvering valve 39. To the annular groove 56 is connected an axial groove 69 provided in the peripheral surface of the plug 51 and the groove 69 has a plane of symmetry common with the bores 68 68 which plane includes the axis of rotation of the plug 51. Pressure reduction grooves 57 58 FIG. 7, are provided in the peripheral surface of the plug 51 and extend respectively from the groove 69 and the bore 68 under decreasing depth towards each other in parallel planes perpendicular to the axis of the plug 51. Similar reduction grooves 57, 58 extend between the groove 69 and the bore 68 The reduction valve plug 51 in the manoeuvering valve 39 is connected via a conduit 54 to a reversing valve 60 from which a return conduit 55 extends back to said plug 51. By means of servo piston means a the reversing valve 60 can be moved to a position a and can be returned to a position b by means of a handle 60b. In the position depicted in FIG 8 the reduction valve plug 51 is in closed position and both conduits 54. 55 are connected to the atmosphere via the reduction grooves 57 57 the groove '69, the annular groove 56, and the hole 59. Simultaneously herewith the bores 68 68 and the reduction grooves 58 58 are closed. When the plug 51 by means of the handle 52 is turned in counter-clockwise direction to the position depicted in FIG. 9, the reduction grooves 57 58 in a manner Well known in the art will throttle and bleed oil pressure fluid thereby reducing the air pressure in the conduit 54 to the reversing valve 60 and in the position b of the reversing valve 60 depicted in FIG. 1, air under suitably reduced pressure is directed from the conduit 54 via a conduit 61 to the feed motor 18, while the exhaust air from the motor is returned via a conduit 62 and is connected by the reversing valve 60 to the return conduit 55 for being exhausted to the atmosphere via the grooves 69, 56 and the plug 51. In this and adjacent positions of the plug 51 the feed motor 18 is thus driven by compressed air under a feeding pressure which can be reduced at will by angular adjustment of the plug 51 by the handle 52. In the position of the plug 51 depicted in FIG. 10 the bore 68 delivers air under full pressure to the conduit 54 and the reduction grooves 57 and 58 are closed.

Thanks to the symmetrical arrangement of the bores and grooves 0n the plug 51, turning of the handle 52 in clockwise direction from the position depicted in FIG. 8 instead connects the return conduit 55 to receive compressed air of adjustable pressure via bore 68 and the reduction grooves 57 58 while the conduit 54 now will receive the exhaust from the feed motor 18. Hereby the rotational direction of the feed motor 18 can be reversed independently of the reversing valve 60.

In the position a of the reversing valve 60 an air conduit 63 connects the conduit 62 to live pressure in the branch 38, while the conduit 61 is connected to the return conduit 55 and is exhausted via the annular groove 56 and hole 59. Such position a causes reversing of the rotational direction of the feed motor 18.

A compressed air network 70 is connected to the conduit 30 upstream of the main valve 31 for delivering pressure fiuid to a forward limit switch valve 71 and a rear limit switch valve 72 on the feed shell 12, to a control valve 73, as well as to an intermediate valve 74. The limit switch valves 71 and 72 are both provided with contact buttons 71b, 72a, respectively, and upon depression of these buttons the limit switch valves can be moved against the action of return spring means to the respective positions b and a. The control valve 73 is reciprocable between a position b and a position a by pressure fluid actuated servo piston means 73a and 73b connected to the opposite ends of the control valve 73. The intermediate valve 74 can be moved against the action of return spring means by servo pistonmeans 74b from a position a to a position b. The valves 7174 and the network 70 are included in a first serve circuit for the automation. The slide 11 of the rock drill 10 is provided with valve actuators 75, 76 of which the actuator in turning position of the rock drill, by contacting the button 71b of the limit switch valve 71, moves the valve 71 to its position b. In such position compressed air from the network 70 is delivered to a conduit 77, at which instant the servo piston means 73a of the control valve 73 is actuated by pressure fluid so that the control valve 73 is moved over to the position a. Simultaneously herewith the servo piston means 60a of the reversing valve 60 are actuated via a conduit 78 communicating with the conduit 77 so that the reversing valve 60 takes the position a and causes reversing of the feed motor 18.

Movement of the control valve 73 to the position a connects a conduit 79 to the network 70, which via the conduit 79 is connected to a hand valve 64. The hand valve 64- can be moved to a position b by pressure fluid actuated servo piston means 64b whereby the conduit 79 is connected to a conduit 65 delivering pressure fluid to a cylinder 66 fixed co-axially to the valve plug 40 in the manoeuvering valve 39. A piston 90, FIG. 2, is carried for axial movement and has a sliding fit in the cylinder 66. The piston 90 carries a plunger thereon which via a bore co-axial with plug 40 can project into the diametrical through passage 37 in the plug 40 when the cylinder 66 receives pressure therein. The projected end of the plunger 80 seats on a rubber washer 91 which by means of a screw is connected to the interior of the plug 40. As a result the passage 37 is throttled down or substantially entirely closed by the projected plunger 80.

When the conduit 65 is pressurized the cylinder 66 thus will receive air under pressure and will close or throttle the through passage 36 of the manoeuvering valve 39 by means of the plunger 80. The hand valve 64 can be moved to a position a and returned to a position b by means of a handle 64a. In the position a the conduit 65 and the cylinder 66 are exhausted to the atmosphere via hand valve 64 so that the plunger 80 and the piston 90 can be moved axially outwardly by the pressure in the passage 36 whereby the passage 37 of the valve plug 40 is opened.

A second servo circuit including air conduits 84 and 81 is coupled to the conduits 61, 62 in parallel with the feed motor 18. When the conduit 61 is pressurized, that is to say during forward feed movement of the rock drill along the shell 12, the pressure is transmitted via conduit 84 to the servo piston means 74b of the intermediate valve 74 moving the latter to the position b depicted in FIG. 1. In this position pressure fluid taken from the network 70 of the first servo system is passed via a conduit 82 to the servo piston means 50a of the flushing valve 50 whereby the valve 50 is kept in the position a depicted in FIG. 1. If live pressure is directed to the other conduit 62 of the feed motor 18, such being the case during reverse rotation of motor 18, the servo conduit 81 of the second servo system will be pressurized and will actuate the servo piston means Stlb of the flushing valve 50. This moves the flushing valve 50 to the position b so that the delivery of flushing Water in interrupted and delivery of flushing air is started from the conduit 47 via the flushing valve 50 to the hose or conduit 49.

The network 7d of the first servo circuit leads via the rear limit switch valve 72 in the position 12 thereof on to a conduit 85. The conduit 85 is connected to a starting valve 87 actuatable by means of a handle 87a by which the starting valve 87 can be moved against the action of return spring means from a normal position b to a starting position a. In the normal position b the conduit 85 communicates with a conduit 89 which is connected to the servo cylinder 34 of the main valve 31 to the underside of the servo diaphragm 33 thereof. The conduits 85, 89 and the starting valve 87 are included in a third servo circuit forming a holding circuit for the main valve 31 for keeping the latter open. When the holding circuit is interrupted as a result of the actuator 76 of the rock drill contacting the button 72a of the rear limit switch valve 72, which moves the valve 72 to its position a connecting the conduits 89, 85 and the servo diaphragm to the atmosphere, the main valve 31 is closed by the spring 35.

In the position a of the rear limit switch valve 72, that is to say when the rock drill 10 is in its starting position, the network 70 is connected by the rear limit switch valve 72 on the one hand to a conduit 95 communicating with the servo piston means 731) of the control valve 73 and on the other hand to a conduit 94 connected to the servo piston means 64b of the hand valve 64. The servo piston means 64b moves the valve 64 to its position b illustrated in FIG. 1 if the valve by some reason should not be in that position. The servo piston means 73b cause return of the control valve 73 to the position b depicted in FIG. 1 in which the conduits 79 and 65 are exhausted via the control valve 73 and the plunger 80 can be moved outwardly by the pressure arising in the passage 36 of the manoeuvering valve 39 so that passage 37 of the plug 40 is opened.

In preparation for the start the manoeuvering valve 39 is set by means of the intercouplcd handles 45, 41 to provide a suitable flow of flushing water and compressed air, the latter for driving the impact motor of the rock drill 10. Similarly a suitable pressure is selected in the conduit '54 to the feed motor 18 by manipulating the handle 52. Additionally the reversing valve 60 is moved to the position b by means of the handle 60b.

The starting valve 87 is used when the rock drill 10 is in its starting position abutting against rear abutment 13. For purposes of starting the drilling cycle valve 87 is depressed by means of the handle 87a and moved to the position a. In this position a conduit 96 communicating with the conduit 30 upstream of the main valve 31 is connected directly to the conduit 89 whereby the underside of the servo diaphragm 33 is pressurized. This causes the main valve 31 to open allowing air under pressure on the one hand to pass to the plug and to start the impact motor of the rock drill 10 and on the other hand via the reduction valve plug 51 to start the feed motor 18. The handle 87a can be released as soon as the rock drill 10 and its valve actuator 76 as a result of the forward feed movement thereof have left the rear limit switch valve '72 thanks to the third servo circuit 85, 87, 89, with the valve 87 returned by its return spring means to the position b thereof providing a holding circuit for the main valve 31. Simultaneously herewith the rear limit switch valve 72 is returned to the position b in which the conduits 95 and 94 and the servo piston means 73b, 64b connected thereto are exhausted to the atmosphere. The forward feed movement and drilling now continues until the full drilling depth has been reached, such depth being defined by the adjustable position of the forward abutment 14 and of the forward limit switch valve 71 on the shell 12. As described above the forward valve actuator 75 displaces the forward limit switch valve 71 to its position b when the rock drill reaches the abutment 14, at which instant the first servo circuit 70, 77, 78 through the intermediary of said valve 71 and reversing valve 60 causes reverse rotation of the feed motor 18 by throwing of the reversing valve 60 and changing of the direction of flow in the conduits 61, 62. Simultaneously herewith the pressure fluid delivery to the impact motor is throttled or closed by the plunger 80 in the plug 40 of the manoeuvering valve 39'. Switching of the pressures in the conduits 61, 62 also causes actuation of the second servo circuit 81, 84 so that the delivery of flushing water is interrupted as described above and delivery of flushing air is started via the conduit 47.

The rock drill 10 is now returned to its starting position by the feed motor 18 while the impact motor thereof is inactive. Upon commencement of the backward feed movement the forward limit switch valve 71 is returned by the action of its return spring means to the position a in which the conduits 77, 7 8 and the servo piston means 73a, 60a are exhausted via said valve 71. Returning to the starting position the rock drill it) again reaches the abutment 13 at which instant the valve actuator 76 will move the rear limit switch valve 72 to its position a exhausting the third servo circuit 85, 87, 88 so that the main valve 31 is closed. Hereby the drilling cycle is terminated.

In case the drill steel should stick during drilling, the operator by manual actuation of the handle 6% obviously is in position to cause a momentary backward feed of the rock drill 10 and a new advancing attempt until drilling can proceed normally. During each such reversal the flushing will change its character because of the second servo circuit 81, 84 and its actuation of the flushing valve 50. As long as the rock drill moves towards the rock face one thus receives flushing by water, but during backward movement of the rock drill an intense flushing by air is efiective to keep the drill hole clean. As an alternative the feed motor '18 can be reversed manually also by actuation of the handle 52 of the reduction valve plug 51, and in this case the character of the flushing will still change with the feed direction of the rock drill 10. Should the steel stick during backward movement of the rock drill 10, the impact motor if necessary can be started by moving the hand valve 64 by the handle 64a to its position a whereby the plunger 80 is allowed to be moved aside by the pressure fluid in the passage 36 and the impact motor will receive compressed air via the plug 40 of the manoeuvering valve 39. By separate manipulation of the handles 52, 41 and 45 the drilling can be controlled entirely manually. The amount of flushing water delivered to the drill steel can be made independent of the manipulation of the plug 40 by retraction of the latch 46. Such independent flushing by water can be important in connection with starting of drill holes under diflicult conditions. During entirely manual operation one can additionally use the handles 60b, 64a and 87a.

In FIG. 1 the manoeuvering valve 39 is provided with a bore 92 tightly closed by a plug 67 and coaxial with the reduction valve 51. In FIG. 2 there is shown an extra valve plug 100 sealingly inserted in the bore 92. The additional plug 100 is used when the rock drill is provided with a separate rotation motor, in which case the rotation motor receives compressed air via the valve plug 100 by which the flow direction and the pressure of the delivered air is controlled by turning of the plug. Such turning is performed by means of a handle 101 and the construction of the plug 100 and its operation will be identical with the above described reduction valve plug 51. To the valve plug 100 are connected air conduits 102 and 103 leading to the rotation motor 104, FIG. 11, which for example may be provided in the front portion of the rock. drill 10.

The modified pneumatic automation circuitry illustrated in FIG. 11 represents a simplified automatic rock drilling means including only the manoeuvering valve 39, the reversing valve 60, the hand valve 64 and the forward limit switch valve 71. Instead of the omitted components there is included a shuttle valve 105 in the circuitry operable by the aid of a reciprocating valve ball or other valve member. The shuttle valve 105 is connected by means of a conduit 106 to the conduit 78, which extends between the forward limit switch valve 71 and the servo pistonmeans 64a of the reversing valve 60. Another conduit 107 connects the shuttle valve 105 to the return conduit and a third conduit 108 connects said valve 105 to the servo piston means 64b of the hand valve 64. In its position a the hand valve 64 exhausts the conduit 65 to the atmosphere. In its position b the hand valve 64 connects a corn duit 109 which is in communication with the branch 38 directly to the conduit 65 and the cylinder 66 for the projection of the plunger 80.

The automatic drilling cycle is normally started when the rock drill 10 occupies starting position in contact with the abutment 13 of the shell 12 by moving by means of the handles 6% and 64a the valves 60, 64 to their respective positions b and a illustrated in FIG. 11. Compressed air is delivered from the source to the conduits 30, 38, 70 via some suitable conventional control valve, not shown. The handles 41, 45, 52 and 101 of the manceuvering valve 39 are adjusted to provide appropriate feed, percussive action, flushing and rotation during drilling whereupon the drilling cycle may continue automatically.

When the desired drill hole depth has been reached, the valve actuator will throw the limit switch valve 71 by means of the button 71b to the position b so that air under pressure from the network 70 will be delivered to the conduit 78 and will reverse the reversing valve 60 by means of the servo piston means 60:: to the position a thereof such as to reverse'the feed motor 18. From the conduit 78 pressure fluid simultaneously therewith will enter the conduit 106 moving the ball of the shuttle valve 105 to the position b and connecting the conduit 108 to live pressure, whereby the hand valve 64 will be moved to its position b by the servo piston means 64b thereof. In this position of the hand valve 64 pressure fluid from the pressure conduit 109 passes the valve 64 and the conduit 65 and pressurizes the cylinder 66 of the manoeuvering valve plug 40, which causes the plunger 80 to close or to throttle the passage 37 of the plug 40 and to interrupt the delivery of power to the impact motor.

Under the backward feed movement of the rock drill 10 which in this embodiment is performed without changing the flushing character at all, the forward limit switch valve 71 under the action of its spring means returns to the position depicted in FIG. 11, causing decompression to the atmosphere of the conduit 78 and of the servo piston means 60a and 64b. Backward feed movement continues 8 until the rock drill 10 against the action of the feed motor 18 is stopped by the abutment 13. The rock drill 10 re mains in this position while flushing by water and rotation and pressurization of the feed motor 18 continues until the next drilling cycle is started in the above described manner.

In the position depicted in FIG. 11 the pressure in the return conduit 55 will be low and at the most will be able to move the ball of the shuttle valve to its position a. With the ball in such position the servo piston means 64b by reason of the frictional resistance therein and in the hand valve 64 will, however, stay in their positions unmoved by the return pressure in conduit 108. In the position a the shuttle valve 105 makes possible manual reversing of the feed motor 18 by actuation of the handle 52 and reversing of the reduction valve plug 51. Hereby the return conduit 55 is pressurized which is the case also with the conduits 107, 108 and the servo piston means 64b. In this state the shuttle valve 105 in its position a keeps the conduit 106 closed and prevents unintentional pressure actuation of the servo piston means 60:; of the reversing valve 60.

What I claim is:

1. In automatic rock drilling means for pressure fluid actuated rock drills reciprocably guided on an elongated supporting shell therefor, a drill steel, a rock drill for actuating said drill steel, a reversible pressure fluid actuated feed motor on said shell operatively connected to said rock drill for imparting forward and backward feed movement thereto along said shell, a source of pressure fluid, and a pressure fluid supply line connecting said rock drill to said power source, the combination which comprises a forward limit switch valve forwardly on said shell for cooperation with and actuatable by said rock drill in a forward position thereof on said shell, a pair of pressure fluid lines alternately connectable to said power source and connected to said feed motor for imparting by forward or reverse movement thereof respectively forward or backward feed movement to said rock drill, a reversing valve connected to said pair of lines, said reversing valve being shiftable between a forward and a backward feed position for alternately connecting one or the other of the lines of said pair to said source, pressure fluid actuated servo motor means connected to said reversing valve for the movement thereof to said backward feed position, means actuatable at will for the movement of said reversing valve to said forward feed position, and a first servo circuit connected to said source and including said forward limit switch valve and said servo motor means and operable to create a pressure condition in said servo motor means causing movement of said reversing valve to said backward feed position when said forward limit switch means is actuated by said rock drill.

2. Automatic rock drilling means according to claim 1 which includes cooperating pressure fluid actuated servo motor and control means in said power supply line to said rock drill movable to cut down the supply of pres sure fluid to said rock drill upon actuation of said servo motor means of said control means, and means coupled to said first servo circuit and responsive to said rock drill actuating said forward limit switch means for actuating said servo motor means of said control means.

3. Automatic rock drilling means according to claim 1 in which there is provided a rear limit switch valve rearwardly on said shell actuatable by said rock drill for defining a starting position therefor on said shell, a main valve connected between said source on the one hand and said pressure fluid supply line to said rock drill, and said pair of lines to said feed motor on the other hand, and an additional servo circuit connectable to said source and including said rear limit switch valve, said additional servo circuit being coupled to said main valve in a manner to cause it to close the pressure fluid supply to said rock drill as well as to said feed motor when said rearward limit switch valve is actuated by said rock drill.

4. Automatic rock drilling means according to claim 1 in which a flushing valve movable between a first position and a second position thereof is adapted to direct flushing liquid to said drill steel in said first position and to direct flushing air to said drill steel in said second position thereof, there being provided a second servo circuit connected to said pressure fluid lines of said feed motor in parallel with said feed motor and operatively connected to said flushing valve in a manner to keep said flushing valve in its first position during forward feed movement of said rock drill and in said second position during backward feed movement of said rock drill.

5. Automatic rock drilling means according to claim 4 in which said flushing valve is provided with servo piston means operatively connected to said second servo circuit for actuation of said flushing valve.

6. In automatic rock drilling means for rock drills reciprocably guided on an elongated supporting shell therefor, a drill steel, a rock drill provided with a pressure fluid driven motor for the actuation of said drill steel, a reversible pressure fluid actuated feed motor on said shell operatively connected to said rock drill for imparting forward and backward feed movement thereto along said shell, a source of pressure fluid, and a pressure fluid supply line connecting said rock drill to said pressure fluid source, the combination which comprises a forward limit switch valve forwardly on said shell for cooperation with and actuatable by said rock drill in a forward position thereof on said shell, a pair of pressure fluid lines alternately connectable to said pressure fluid source and connected to said feed motor for imparting by forward or reverse movement thereof respectively forward or backward feed movement to said rock drill, a reversing valve connected to said pair of lines, said reversing valve being a two-position valve shiftable be tween a forward and a backward feed position for alternately connecting one or the other of the lines of said pair to said pressure fluid source, servo piston means connected to said reversing valve for the movement thereof to said backward feed position, and a first pressure fluid servo circuit connected to said source and including said forward limit switch valve and said servo piston means and operable to connect said pressure fluid source to said servo piston means when said limit switch valve means is actuated by said rock drill.

7. Automatic rock drilling means according to claim 6 in which there is provided a plunger in said pressure fluid supply line movable from an inactive to an active position to cut down the pressure fluid flow through said pressure fluid supply line, servo piston means connected to said plunger for the movement thereof to said active position upon said servo piston means being connected to said pressure fluid source, and means coupled to said first servo circuit and responsive to said rock drill actuating said forward limit switch valve for connecting said servo piston means of said plunger to said pressure fluid source.

8. Automatic rock drilling means according to claim 7 in which a control valve is provided in the connection between said pressure fluid source and said servo piston means of said plunger, said control valve having a first position for exhausting said servo piston means to the atmosphere thereby to cause movement of said plunger to said inactive position thereof and a second position connecting said pressure fluid source to said servo piston means thereby to move said plunger to active position, a rear limit switch valve rearwardly on said shell connected to said first servo circuit and actuatable by said rock drill in a starting position thereof on said shell, and servo piston means having flow connection with said forward and rear limit switch valves and connected to said control valve for moving said control valve to said first position as a result of actuation of said rear limit switch valve and to said second position as a result of actuation of said forward limit switch valve.

9. Automatic rock drilling means according to claim 6 in which a manually adjustable reducing valve connected to said pressure fluid source is provided upstream of said reversing valve, said reducing valve being connectable via said reversing valve for supplying pressure fluid to the pressure fluid line of said feed motor which during the forward feed movement of said rock drill receives pressure fluid for driving said feed motor.

10. Automatic rock drilling means according to claim 9 in which said reducing valve during forward feed movement of said rock drill is coupled across said pair of power lines to said feed motor for manual reversing of the pressure fluid flow therein independently of said reversing valve.

11. Automatic rock drilling means according to claim 9 in which said reversing valve in the backward feed position thereof is coupled to said pressure fluid source to deliver pressure fluid to said feed motor under full line pressure independently of said reducing valve.

12. Automatic rock drilling means according to claim 6 in which said reversing valve has manual actuating means thereon for the movement thereof to said forward feed position.

13. Automatic rock drilling means according to claim 6 in which there is provided a rear limit switch valve rearwardly on said shell actuatable by said rock drill for defining a starting position therefor on said shell, a main valve connected between said pressure fluid source on the one hand and said pressure fluid supply line to said rock drill and said pair of pressure fluid lines to said feed motor on the other hand, said main valve having pressure fluid actuated servo piston means connected thereto for the opening thereof, return spring means for closing said main valve, and an additional servo circuit being a pressure fluid actuated holding circuit connectable to said source to actuate the servo piston means of said main valve by pressure fluid thereby to keep said main valve open, and said limit switch valve being coupled to exhaust said additional servo circuit to the atmosphere when said rock drill reaches its starting position and to connect it to said source in other positions of said rock drill.

14. Automatic rock drilling means according to claim 13 in which a manually actuatable starting valve is included in said additional servo circuit, said starting valve having a starting position for connecting said servo piston means of said main valve directly to said source until said additional servo circuit is connected to said source via said rear limit switch valve as a result of forward movement of said rock drill.

15. In automatic rock drilling means for rock drills reciprocably guided on an elongated supporting shell therefor, a drill steel, a rock drill for actuating said drill steel, a reversible feed motor on said shell operatively connected to said rock drill for imparting forward and backward feed movement thereto along said shell, and a source of power, the combination which comprises a pair of power lines alternately connectable to said power source and connected to said feed motor for imparting by forward or reverse movement thereof respectively forward or backward feed movement to said rock drill, reversing means connected to said pair of power lines and to said power source for alternately connecting one or the other of said lines to said power source, a flushing valve movable between a first position and a second position thereof and adapted to direct flushing liquid to said drill steel in said first position and to direct flushing air to said drill steel in said second position thereof, and a servo circuit connected to said power lines of said feed motor in parallel with said feed motor and operatively connected to said flushing valve in a manner to keep said flushing valve in its first position during forward feed movement of said rock drill and in said second position during backward feed movement of said rock drill.

16. Automatic rock drilling means according to claim 15 in which said flushing valve is provided with servo piston means operatively connected to said servo circuit for actuation of said flushing valve.

17. In automatic rock drilling means for rock drills reciprocably guided on an elongated supporting shell therefor, a drill steel, a rock drill for actuating said drill steel, a reversible feed motor on said shell operatively connected to said rock drill for imparting forward and backward feed movement thereto along said shell, a source of pressure fluid, and a pressure fluid supply line connecting said rock drill to said source, the combination which comprises a limit switch valve forwardly on said shell for cooperation with and actuatable by said rock drill in a forward position thereto on said shell, a pair of lines alternately connectable to said source and connected to said feed motor for imparting by forward or reverse movement thereof respectively forward or backward feed movement to said rock drill, a two-position reversing valve connected to said pair of lines, said reversing valve being shiftable between a forward and a backward feed position for alternately connecting one or the other of the lines of said pair to said source, pressure fluid actuated servo motor means connected to said reversing valve for the movement thereof to said means and operable to create a pressure condition in i said servo motor means causing movement of said reversing valve to said backward feed position when said limit switch valve is actuated by said rock drill, and rear abutment means on said shell cooperating with said rock drill for stopping the backward feed movement thereof against continued action of said feed motor thereby to define a starting position for said rock drill on said shell.

18. A pressure fluid actuated servo motor and valve device for the control of fluid flow in a conduit forming part of a pressure fluid automation circuit comprising in combination with said conduit, valve housing, a pair of passages in said housing and included in said conduit, a

servo motor housing rotatably and sealingly journaled in said valve housing between said passages, a through passage in and transverse to said servo motor housing and aligned with said passages with angular adjustment of said servo motor housing in said valve housing controlling fluid flow therethrough, a plunger axially movably disposed in said servo motor housing and longitudinally movable between a position laterally of said through passage and a position with said plunger projecting into and obstructing said through passage, means for the angular adjustment of said servo motor housing in said valve housing, and pressure fluid actuated servo motor means in said servo motor housing connected to said plunger for moving the latter to said projected and lateral positions thereof.

19. A pressure fluid actuated servo motor and valve device as recited in claim 18 in which said servo motor housing includes a cylinder disposed within said housing axially thereof and a servo piston in sliding and sealing cooperation with said cylinder and connected to said plunger, means for supplying pressure fluid to the end of said cylinder remote from said plunger for causing said piston to move said plunger to the projected position thereof, and means for relieving fluid pressure in said remote end of said cylinder for causing the pressure in said through passage to move said plunger to the lateral position thereof.

References Cited UNITED STATES PATENTS 2,806,448 9/1957 Maxson 17377 3,146,591 9/1964 Turner 137637.4 X 3,191,692 6/1965 Ekwall 173-77 3,204,706 9/1965 Jonsson 173-19 X 3,273,595 9/1966 Novak 137-6374 3,307,637 3/1967 Jonsson 173-49 X ERNEST R. PURSER, Primary Examiner.

FRED C. MATTERN, Exan'ziner.

L. P. KESSLER, Assistant Examiner. 

